As Hillary Clinton's once-commanding lead in the polls collapses, Democrats are panicking at the possibility that Donald Trump actually could be elected president of the United States.

They can relax. Strip away the incendiary rhetoric, and a Trump presidency in many ways will be exactly what Democrats want — a third Obama term.

While Trump attacks President Barack Obama on the campaign trail as "the worst president, maybe in the history of our country," on issue after issue Trump has mimicked not only Obama's policies but also Obama's own language to argue for them.

Take spending and debt. One of the great liberal achievements of the Obama presidency was the massive 2009 stimulus, which included $550 billion in government spending to fix what Obama called "our crumbling roads, bridges, and schools" — even though it was not paid for with spending cuts elsewhere. This was the bill that helped set off the tea party revolt of 2010. Nearly every Republican in Congress voted no.

Well, in August, Trump said that as president he plans to spend — wait for it — more than $500 billion on new infrastructure projects — which, he boasted, is "at least double" what Clinton plans to spend. Where would Trump get the money? By adding to the national debt. "This is the time to borrow," he told CNBC, because "rates are so low." Trump further explained that "normally, you would say you want to reduce your debt, and I would like to reduce debt, too," but we can't because we have "a tremendous infrastructure problem."

Or take the Middle East. In announcing his drawdown of U.S. forces in Afghanistan in June 2011, President Obama declared that the United States could no longer afford to deploy troops across the world. "Over the last decade, we have spent a trillion dollars on war, at a time of rising debt and hard economic times," Obama said, adding that "it is time to focus on nation-building here at home." At the time, former House speaker Newt Gingrich ripped Obama's speech as "dangerously misinformed," declaring that a "tsunami of violence is building offshore" and "this administration is crippling the United States and every country in the world by failing to protect those who help us."

Well, Donald Trump has said the exact same thing as Obama. "We are spending trillions of dollars in the Middle East, and the infrastructure of our country is disintegrating," Trump has said, adding that "we have to build our own country, and that's what we have to focus on."

Withdrawing from a dangerous world to save money and focus on nation-building here at home — that is the Obama policy. And apparently it will remain U.S. policy in a Trump administration.

Or take American exceptionalism. Back in 2009, Republicans blasted Obama when he declared, "I believe in American exceptionalism, just as I suspect that the Brits believe in British exceptionalism and the Greeks believe in Greek exceptionalism." Former New York mayor Rudy Giuliani said, "I know this is a horrible thing to say, but I do not believe that the president loves America," adding that Obama's comments show "a stark lack of moral clarity."

Well, you know who shares that lack of moral clarity? Trump. At a Texas tea party event in 2015, Trump said virtually the same thing as Obama: "Look, if I'm a Russian, or I'm a German ... I don't think it's a very nice term. We're exceptional; you're not ... I think you're insulting the world ... I never liked the expression."

At least Obama paid lip service to American exceptionalism; Trump rejects it outright.

And that's just scratching the surface. Obama has slammed "fat-cat bankers on Wall Street." Trump says hedge-fund managers are "getting away with murder." Obama told Republicans in Congress who opposed a minimum-wage hike, "If you truly believe you could work full time and support a family on less than $15,000 a year, try it." Trump says, "I don't know how people make it on $7.25 an hour ... I would like to see a [minimum wage] increase of some magnitude." Obama blasts Republicans for what he called efforts at "privatizing Social Security." Trump says, "Every Republican wants to do a big number on Social Security, they want to do it on Medicare, they want to do it on Medicaid ... And we can't do that." The list goes on and on.

In some areas, such as Supreme Court nominations, a Trump presidency would probably be a setback for Democrats. But in other areas, Trump may actually be an improvement for liberal Democrats over Obama. On trade, Trump opposes the hated Trans-Pacific Partnership that Obama negotiated. On health care, he supports single-payer and has said, "This is an un-Republican thing for me to say ... I am going to take care of everybody ... the government's gonna pay for it." Even on immigration, Trump's inflammatory rhetoric aside, he actually supports giving legal status to almost all of the 11 million illegal immigrants in the United States — they just have to "touch back" in their home country briefly to get it. Trump may actually be the president most likely to deliver on the Democratic dream of comprehensive immigration reform.